1. Field of the Invention
The present invention relates to a semiconductor device.
2. Related Background Art
A semiconductor device using a nitride semiconductor such as a High Electron Mobility Transistor (HEMT) and the like is sometimes used as a high-frequency output amplification element. The HEMT is required to have high output and high linearity. Two-dimensional electron gas (2DEG) with high concentration occurs in the vicinity of an interface between a channel layer and an electron supply layer of a HEMT using gallium nitride (GaN). A semiconductor device including the channel layer formed by GaN is disclosed in Japanese Unexamined Patent Application Publication No. 2008-306025.